BASICS

What Do The Numbers On Tyres Mean


When you glance at your tyres, you'll see a perplexing variety of letters and words. Worse, it all seems to be very random. It's as if they're meant to perplex tyre fitters and pass on hidden signals. However, there is a system hidden behind the nonsense. You will be able to comprehend it, and it is well worth your time to do so. Even if it's only so you can befuddle people and enjoy watching them try to understand the notion.

Have you ever wondered what the numbers on car tyres mean? Or, more significantly, what should you take away from them? Now you don't have to wonder any longer, since we'll solve the riddle of your tyres.

The brand name and model name will be in the largest lettering on the side of your tyre, but the cryptic collection of characters and numbers (sometimes smaller, sometimes not) will tell you more. They will resemble the following:


Tyre Numbers Explained


Numbers on tyre, what do they mean? The section width (225), aspect ratio (45), construction (R), rim diameter (19), load index (92) and speed rating (W) are all represented by these numbers

The section width (225) is the tyre's width in millimetres, which is 225mm in this example. This measurement is measured from the maximum width of the tyre's sidewall's mid point to the same position on the opposite sidewall, thus it's not only the width of the tread, but the tyre's maximum overall width when seen from below.

The aspect ratio (45) or profile is the sidewall height represented as a percentage of the section width of the tyre, which in this example is 45 percent of 225mm, or 101.25mm.

The manufacturer's name is usually written in the largest font, although the rest of the information is more crucial.

When we speak about "low profile" tyres on performance vehicles, we're talking about the ones that appear like a black rubber band wrapped around a big alloy wheel. A low profile tyre has an aspect ratio of 50% or less, with ultra-low profile tyres on supercars and the like having an aspect ratio of 30% or less.

Finally, the structure (R) denotes the tyre carcass construction style. R stands for "Radial," which is by far the most popular kind of tyre construction today, with radial construction tyres used on almost all new automobiles.


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